• Transactions on Electrical and Electronic Materials
• /
• 제18권5호
• /
• pp.257-260
• /
• 2017

In this paper, we present the design of a 4.5 V low dropout (LDO) voltage regulator implemented in the 130 nm CMOS process. The design uses a two-stage cascaded operational transconductance amplifier (OTA) as an error amplifier, with a body bias technique for reducing dropout voltages. PMOS is used as a pass transistor to ensure stable output voltages. The results show that the proposed LDO regulator has a dropout voltage of 32.06 mV when implemented in the130 nm CMOS process. The power dissipation is only 1.3593 mW and the proposed circuit operates under an input voltage of 5V with an active area of $703{\mu}m^2$, ensuring that the proposed circuit is suitable for low-power applications.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제14권4호
• /
• pp.443-450
• /
• 2014

This paper presents a 20-Gb/s optical receiver circuit fabricated with standard 65-nm CMOS technology. Our receiver circuits are designed with consideration for parasitic inductance and capacitance due to bonding wires connecting the photodetector and the circuit realized separately. Such parasitic inductance and capacitance usually disturb the high-speed performance but, with careful circuit design, we achieve optimized wide and flat response. The receiver circuit is composed of a transimpedance amplifier (TIA) with a DC-balancing buffer, a post amplifier (PA), and an output buffer. The TIA is designed in the shunt-feedback configuration with inductive peaking. The PA is composed of a 6-stage differential amplifier having interleaved active feedback. The receiver circuit is mounted on a FR4 PCB and wire-bonded to an equivalent circuit that emulates a photodetector. The measured transimpedance gain and 3-dB bandwidth of our optical receiver circuit is 84 $dB{\Omega}$ and 12 GHz, respectively. 20-Gb/s $2^{31}-1$ electrical pseudo-random bit sequence data are successfully received with the bit-error rate less than $10^{-12}$. The receiver circuit has chip area of $0.5mm{\times}0.44mm$ and it consumes excluding the output buffer 84 mW with 1.2-V supply voltage.

• 한국산학기술학회논문지
• /
• 제16권9호
• /
• pp.6247-6253
• /
• 2015

본 논문은 병렬 오차 증폭기 구조를 적용하여 과도응답특성 개선한 LDO 레귤레이터를 제안한다. 제안하는 LDO 레귤레이터는 고 이득, 좁은 주파수 대역의 오차증폭기 (E/A1)와, 저 이득, 넓은 주파수 대역의 오차증폭기 (E/A2)로 이루어지며, 두 오차증폭기를 병렬 구조로 설계해서 과도응답특성을 개선한다. 또한 슬루율을 높여주는 회로를 추가하여 회로의 과도응답특성을 개선하였다. 극점 불할 기법을 사용하여 외부 보상 커패시터를 온 칩 화하여 IC 칩 면적을 줄여 휴대기기 응용에 있어서도 적합하게 설계 하였다. 제안된 LDO 레귤레이터는 매그나칩/하이닉스 $0.18{\mu}m$ CMOS 공정을 사용하여 회로설계 하였고 칩은 $500{\mu}m{\times}150{\mu}m$ 크기로 레이아웃을 실시하였다. 모의실험을 한 결과, 2.7 V ~ 3.3 V의 입력 전압을 받아서 2.5 V의 전압을 출력하고 최대 100 mA의 부하 전류를 출력한다. 레귤레이션 특성은 100 mA ~ 0 mA에서 26.1 mV의 전압변동과 510 ns의 정착시간을 확인하였으며, 0 mA에서 100 mA의 부하 변동 시 42.8 mV의 전압 변동과 408 ns의 정착 시간을 확인하였다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2004년도 하계종합학술대회 논문집(2)
• /
• pp.395-398
• /
• 2004

High-linearity voltage-controlled current sources (VCCSs) circuits for wide voltage-controlled oscillator and automatic gun control were proposed. The VCCS consists of emitter follower for voltage input, two common-base amplifier which their emitter connected for current output, and current mirror which connected the two amplifier for large output current. The VCCS used only five transistors and a resistor without an extra bias circuit. Simulation results show that the VCCS has current output range from 0mA to 300mA over the control voltage range from 1V to 4.8V at supply voltage 5V. The linearity error of output current has less than $1.4\%$ over the current range from 0A to 300mA.

• 전자공학회논문지D
• /
• 제35D권8호
• /
• pp.69-75
• /
• 1998

We demonstrate wavelength conversion of 2.5Gb/s optical signals by four-wave mixing (FWM) in a semiconductor optical amplifier (SOA). We investigate the effect of input pump and signal powers on the coversion efficiency, optical signal-to-noise ratio (OSNR) and extinction ratio to be a measure of performance in a wavelength converter. As a result, we show that the maximum bit error rate (BER) performance can be obtained by co promising among high-vonversion efficiency (minimum Pprobe), high-OSNR (maximum Pprobe) and low-cross-gain saturation effects (Pprobe kept at least 6dB weaker than Ppump). In our experiment, we obtain optimum performance at +3 dBm pump power and -6dBm signal power. The power penalty incurred in the wavelength conversion can be minimized by careful selection of the input pump and signal powers. We show that about 0.5dB power penalty for 3.2nm wavelength coversion at 10-10 BER is achievable.

• 한국통신학회논문지
• /
• 제24권6A호
• /
• pp.855-863
• /
• 1999

최근 들어 다양한 종류의 정보를 원하는 속도와 서비스품질(QOS)로 전송하고자 하는 Multi-Rate CDMA 시스템들에 대한 연구가 활발하다. 본 연구에서는 다양한 종류의 정보를 보내는데 있어서 쉽게 기존의 CDMA 시스템과 융화 될 수 있으며, 사용자가 요구하는 QOS와 전송 속도를 만족시킬 수 있는 Multi-Code CDMA 시스템에서 주요한 요소로 고려되고 있는 전력 증폭기의 비선형성을 고려하여 Multi-Code CDMA 시스템의 성능을 분석하였다. 분석에 사용한 비선형 증폭기의 모델링에는 다항식을 사용하였으며, 분석 결과 특히 주파수 선택적 페이딩의 경우 비선형에 의한 영향이 AWGN 채널에 비하여 훨씬 더 큼을 알 수 있었다.

• 전자공학회논문지A
• /
• 제31A권12호
• /
• pp.135-141
• /
• 1994

A linear BiCMOS operational transconductance amplifier (OTA) is described. It consists of a CMOS linear transconductor and a bipolar translineear current gain cell followed by three CMOS current mirrors. The proposed circuit has comparable linearity and temperature stability but superior dc characteristics to its bipolar counterpart. A test circuit with a transconductance of 47.3$\mu$s has been simulated. Simulation results show that a linearity error of less than $\pm$1 percent over an input volgate range from -1.0 to 1.0 V and a output dc offset current as small as-3.6 nA can be obtained.

• 한국전자파학회:학술대회논문집
• /
• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
• /
• pp.108-112
• /
• 2003

A feedforward amplifier, which is composed of several components, is an open loop system. Therefore, feedforward amplifiers are apt to deteriorate the performance according to the environmental changes even though the cancellation performance and the linearization bandwidth of feedforward systems are superior to other linearization methods. A control method is needed for maintaining the original performance of feedforward amplifiers or to keep the performance within a little error bounds. In this paper, an adaptive control method, which has a good convergence characteristic and is easy to implement, is suggested. The characteristics of the suggested control method compare with the characteristics of other control methods and the simulation results are presented.

• Journal of the Optical Society of Korea
• /
• 제3권2호
• /
• pp.80-85
• /
• 1999

We propose and demonstrate a new scheme for suppression of output distortion in an open-loop gyroscope employing an erbium-doped fiber amplifier/source (FAS). In addition to the main modulation for the rotation rate measurement, a small auxiliary modulation at a different frequency is used to extract an error signal, which is necessary for keeping the quasi-dc component of the feedback signal power at a constant level for varying rotation rate. By active tracking of the optimum modulation condition using this two-frequency modulation scheme, we obtain stable gyro output with suppressed distortion as well as stable FAS characteristics. We also calculate the distortion in the gyro response due to the feedback effect, from which we estimate the FAS gyro output distortion due to the residual ac feedback effect when the dc feedback effect is removed by the proposed scheme. The measured residual deviation agrees reasonably with the estimation.

• 공학논문집
• /
• 제2권1호
• /
• pp.103-111
• /
• 1997

EDFA는 광전송시스템에서 광섬유상에 전파되는 신호가 광섬유의 손실로 인해 약해지게 되는데 미약해진 신호의 광세기를 키워주는 증폭기로서 널리 사용되고 있다. EDFA의 증폭기작을 주요 인자를 가지고 분석함으로써 그 특성을 이해하고 이를 토대로 EDFA 설계시 유용한 기준으로 삼고자 한다. 또한 광전송시스템에서의 EDFA는 자연방출광잡음으로 인해 수신단에서 신호대잡음비를 악화시켜 전송오율을 증가시키게 되는데 이를 억제하기 위한 동작조건 즉 잡음지수의 최소화하는 동작조건에 대해서 논하고자 한다.